Can,t answer the cost question but it is expensive and messy.
I have removed the headlining on my 26ft Centaur agus am not replacing them as theres lots of alternatives in mags etc,
Theres a good thread on SN that I saw updated the other day.
My main problem is condensation on the painted surface that causes mildew over the winter. Am still trying different solutions. Other than that I like the paint finish, easy to clean and maintain.
Would mildew affect you in sunny California?
Post edited to protect the illiterate, keep forgetting the spell check